Sheen has now issued an apology to Kutcher, but says he stands by his criticism of the show, reports tmz.com.

"Dear Ashton, My bad. I was disrespectful to a man doing his best. I got excited and I threw you into the crossfire, but the rest of my statement I stand behind. You however, deserve better. Safety in your travels good sir," he said.

Sheen was fired from the show in March last year after months of erratic behaviour and Kutcher was subsequently hired to take over.